How to add cut out part of an overlapping shape?

[Ryan]

Question:

How to add cutouts to a shape so the underlying graphics of the page show through?

Something like the following, where the circle cuts out the rectangle?

Answer:

You want to use Winding so the inner fills are not filled. Essentially the Winding setting takes care of clipping for you. See the attached C# code for working example. Below is code snippet.

writer.Begin(page, ElementWriter.WriteMode.e_overlay);

builder.PathBegin();

// draw rectangle
builder.MoveTo(200, 500);
builder.LineTo(500, 500);
builder.LineTo(500, 300);
builder.LineTo(200, 300);
builder.LineTo(200, 500);

// draw cutout
builder.MoveTo(400, 400);
builder.CurveTo(400, 427.614, 377.614, 450, 350, 450);
builder.CurveTo(322.386, 450, 300, 427.614, 300, 400);
builder.CurveTo(300, 372.386, 322.386, 350, 350, 350);
builder.CurveTo(377.614, 350, 400, 372.386, 400, 400);

// add additional cutouts here
// ..

Element element = builder.PathEnd();
element.SetWindingFill(false); // Important! to get the cutouts correct
element.SetPathStroke(false);
element.SetPathFill(true);
GState gs = element.GetGState();
gs.SetFillColorSpace(ColorSpace.CreateDeviceCMYK());
gs.SetFillColor(new ColorPt(1, 0, 0, 0)); // cyan
writer.WriteElement(element);

writer.End();